CN212296921U

CN212296921U - LNG multistage immersed pump

Info

Publication number: CN212296921U
Application number: CN202021040609.9U
Authority: CN
Inventors: 朱祖超; 杨世栋; 李晓俊; 张炜; 陈小平
Original assignee: Zhejiang University of Technology ZJUT; Zhejiang Institute of Mechanical and Electrical Engineering Co Ltd
Current assignee: Zhejiang University of Technology ZJUT; Zhejiang Sci Tech University ZSTU; Zhejiang Institute of Mechanical and Electrical Engineering Co Ltd; Zhejiang University of Science and Technology ZUST
Priority date: 2020-06-08
Filing date: 2020-06-08
Publication date: 2021-01-05
Anticipated expiration: 2030-06-08

Abstract

The utility model relates to a centrifugal pump field. The technical scheme is as follows: LNG multistage immersed pump, include by going to back according to the preface and arrange and equal fixed connection's between two liang the anterior segment pump case, middle section pump case and back end pump case, fix the bearing subassembly in the anterior segment pump case, the built-in motor of fixing in the back end pump case, one end is supported by the bearing subassembly and the pump shaft of the motor shaft fixed connection of the other end and built-in motor, set up in the front end pump case and with pump shaft front end fixed connection's inducer, set up a plurality of impellers in the middle section pump case, the cover is established in the impeller outside and a plurality of guide vanes of outer fringe and middle section pump case inner wall fixed connection and is installed on the pump shaft and fix in order to balance. The immersed pump can work in a low-temperature environment, the problem of positioning of the impeller can be effectively solved, the impeller is prevented from generating circumferential displacement and axial displacement, and meanwhile, the axial forces at the two ends of the impeller are balanced with each other, so that the impeller is ensured to run stably, and the overall performance of the pump is improved.

Description

LNG multistage immersed pump

Technical Field

The utility model relates to a centrifugal pump field specifically is multistage immersed pump of LNG.

Background

LNG is an abbreviation for liquefied natural gas (liquefied natural gas) and the main component is methane. LNG is colorless, odorless, non-toxic, and non-corrosive, and has a volume of about 1/600 that is the same volume of gaseous natural gas. Therefore, liquefied natural gas is an effective way for storing and transporting natural gas, and has been rapidly developed in recent years, and a large amount of LNG immersed pumps are required to be used in the transportation and filling processes of the liquefied natural gas. The impeller is used as a core component of the pump, and the positioning accuracy of the impeller can directly influence the overall performance of the pump.

The main method of positioning a typical impeller on a shaft is by means of a shoulder and threads. One side of the impeller hub is tightly close to the shaft shoulder, and the other side of the impeller hub is screwed and fixed on the shaft through a threaded part, so that the axial positioning of the impeller is completed. The positioning mode is simple, but the deviation is easy to exist in the processing process of the pump shaft, and the multi-stage impeller is not suitable for positioning.

Chinese utility model patent (application number "CN 201310262314.4", 2013.06.27 as filed) discloses an impeller location structure, fixes a position the impeller through the taper pin, utilizes interference fit to guarantee can not become flexible to the thickness of axle need not consider the additional strength of keyway, material saving, but this structure is not suitable for microthermal operational environment.

The chinese utility model patent (application number "CN 201520827474.3", application date 2015.10.22) discloses an impeller axial direction locating sleeve, reaches the positioning action through the pressure between locating sleeve and the axle, and this kind of locate mode is simple, reliable, but this structure has only been considered the axial and has not been considered circumference location, and has not been considered the characteristic of locating sleeve material low temperature shrink.

Chinese utility model patent (application number "CN 201720658571.3", 2017.06.07 as filed) discloses a multistage pump impeller fixing device, utilizes the interference fit of axle sleeve and impeller and the screw between axle sleeve and the impeller to guarantee the impeller location, utilizes axial clearance, snap ring and impeller axle sleeve to guarantee the position sleeve axial positioning. However, at the beginning of the design, the impeller adjusting allowance is left between the snap ring and the axial gap, and when the multistage impeller works, the generated axial force can cause the shaft sleeve and the snap ring to axially slide, so that the pump is not stable in operation.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the not enough of above-mentioned background art, provide a multistage immersed pump of LNG, this immersed pump can work under low temperature environment to can effectively solve the location problem of impeller, avoid the impeller to produce circumference and axial displacement, the axial force at impeller both ends is balanced each other simultaneously, thereby guarantees the impeller even running, improves the wholeness ability of pump.

The utility model provides a technical scheme is:

the LNG multistage immersed pump comprises a front-section pump shell, a middle-section pump shell and a rear-section pump shell which are sequentially arranged from front to back and fixedly connected with each other, a bearing assembly fixed in the front-section pump shell, a built-in motor fixed in the rear-section pump shell, a pump shaft, one end of which is supported by the bearing assembly and the other end of which is fixedly connected with a motor shaft of the built-in motor, an inducer arranged in the front-section pump shell and fixedly connected with the front end of the pump shaft, a plurality of impellers arranged in the middle-section pump shell, a plurality of guide vanes sleeved outside the impellers and fixedly connected with the inner wall of the middle-section pump shell at the outer edge, and a balance disc; the method is characterized in that:

each impeller is fixed on the pump shaft through a group of locating sleeve assemblies; the positioning sleeve assembly comprises a positioning sleeve nut section, a positioning sleeve bolt section and a positioning sleeve pin section which are sleeved on the pump shaft and fixedly connected in sequence; the positioning sleeve bolt section is in interference fit with the pump shaft, so that the positioning sleeve bolt section is fixed on the pump shaft; the positioning sleeve bolt section is fixedly connected with the positioning sleeve nut section through a thread pair; the positioning sleeve nut section is fixedly connected with one side of the impeller into a whole through a threaded fastener; the positioning sleeve pin section, the positioning sleeve bolt section and the other side of the impeller are fixedly connected into a whole through a threaded fastener; the pump shaft, the positioning sleeve nut section, the positioning sleeve bolt section, the positioning sleeve pin section and the impeller are coaxially arranged.

The bearing assembly comprises a bearing support frame, a bearing fixed on the bearing support frame and a sleeve fixed in a bearing inner ring; the pump shaft is rotatably positioned in the sleeve; the bearing support frame comprises an inner ring for fixedly mounting a bearing, an outer ring fixed on the inner wall of the front-section pump shell through screws and a plurality of ribs connected between the inner ring and the outer ring in a spoke shape.

The thread pair comprises an internal thread arranged on the inner wall of the nut section of the positioning sleeve and an external thread arranged on the outer wall of the bolt section of the positioning sleeve and matched with the internal thread.

The tail end of the internal thread of the positioning sleeve nut section is provided with a bulge; the initial end of the external thread of the positioning sleeve bolt section is provided with a groove matched with the protrusion, so that the threaded hole of the positioning sleeve nut section is ensured to be corresponding to the threaded hole of the impeller.

A positioning sleeve flat key is arranged on the periphery of the positioning sleeve bolt section; the impeller is positioned on the periphery of the positioning sleeve bolt section through the positioning sleeve flat key so as to ensure that the threaded hole of the positioning sleeve bolt section corresponds to the threaded hole of the impeller.

The outer wall of the pin section of the positioning sleeve is provided with a bolt; and the inner wall of the positioning sleeve bolt section is provided with a slot which is matched with the inserted pin in an inserted manner so as to ensure that a threaded hole of the positioning sleeve bolt section corresponds to a threaded hole of the positioning sleeve pin section.

The threaded holes on the two sides of the impeller are the same in number and are symmetrically distributed so as to offset the axial force generated by the threaded fasteners on the two sides of the impeller.

The number of the threaded holes on each side of the impeller is 4-8.

The positioning sleeve bolt section and the positioning sleeve nut section are both made of austenitic deep-cooled steel; the locating sleeve pin section is made of 9 nickel steel.

The utility model has the advantages that:

1) the impeller is fixed on the pump shaft through the locating sleeve assembly, the pump shaft does not need to be processed, and errors generated by processing are reduced.

2) The impeller and the locating sleeve assembly are fixedly connected through the threaded fasteners, and the threaded holes on the two sides of the impeller are symmetrically distributed, so that axial forces generated by the threaded fasteners on the two sides of the impeller can be mutually offset, and the impeller is guaranteed not to slide axially.

3) The utility model selects the positioning sleeve bolt section and the positioning sleeve nut section as austenite deep-cooling steel, and the positioning sleeve bolt section and the positioning sleeve nut section can utilize the thermal expansion coefficient to connect the pump shaft more tightly along with the reduction of temperature; the locating sleeve pin section is made of 9 nickel steel, the thermal expansion coefficient of the locating sleeve pin section is low, the locating sleeve pin section can ensure that the locating sleeve assembly is more difficult to rotate relatively at a low temperature along with the reduction of the locating sleeve bolt section, and compared with the normal temperature, the low temperature can ensure the connection stability among all parts in the locating sleeve assembly, and the locating sleeve pin section is suitable for a low-temperature working environment.

4) The positioning sleeve flat key is arranged on the periphery of the positioning sleeve bolt section, and the impeller is installed on the periphery of the positioning sleeve bolt section through the positioning sleeve flat key, so that the position of a screw hole of the impeller is determined, and the circumferential positioning of the impeller is guaranteed; all be equipped with buckle structure between position sleeve nut section and the position sleeve bolt section, between position sleeve bolt section and the position sleeve round pin section, when each buckle structure was mutually supported, can guarantee that the screw of impeller, the screw of position sleeve nut section and the screw of position sleeve round pin section can correspond each other.

Drawings

Fig. 1 is a schematic sectional view of the present invention.

Fig. 2 is an enlarged schematic view of a portion a of fig. 1.

Fig. 3 is an enlarged schematic view of a portion B of fig. 1.

Reference numerals:

1. an inducer; 2. a bearing assembly; 3. a locating sleeve assembly; 4. a positioning sleeve flat key; 5. a bushing; 6. an impeller; 7. a guide vane; 8. a balance disc; 9. a built-in motor; 10. a rear pump housing; 11. positioning a sleeve pin section; 12. a positioning sleeve bolt segment; 13. a locating sleeve nut section; 14. a middle pump casing; 15. a pump shaft; 16. a sleeve; 17. a front-section pump housing; 18. an outer ring; 19. ribs; 20. an inner ring; 21. a bearing; 22. a last stage impeller; 23. and (4) a bolt.

Detailed Description

The following further description is made with reference to the embodiments shown in the drawings.

For convenience of description, the left end of fig. 1 is taken as the front, and the right end is taken as the back.

The LNG multistage immersed pump shown in fig. 1 includes a front-stage pump casing 17, a middle-stage pump casing 14, a rear-stage pump casing 10, a bearing assembly 2, an internal motor 9, a pump shaft 15, an inducer 1, a plurality of (five shown in the figure) impellers 6, a plurality of (four shown in the figure) guide vanes 7, and a balance disk 8, which are coaxially arranged. The front section pump shell, the middle section pump shell and the rear section pump shell are arranged sequentially from front to back and are fixedly connected with each other through bolts, an inlet is formed in the front end of the front section pump shell, and an outlet is formed in the rear end of the rear section pump shell.

As shown in fig. 1 and 3, the bearing assembly is arranged in a front-section pump shell; wherein the bearing assembly comprises a bearing support bracket, a bearing 21 and a sleeve 16; the bearing support frame comprises an inner ring 20 for fixedly mounting a bearing, an outer ring 18 fixed on the inner wall of the front-section pump shell through screws and a plurality of ribs 19 connected between the inner ring and the outer ring in a spoke shape; the sleeve is fixed in the inner ring of the bearing. The built-in motor is fixed in the rear-section pump shell. The pump shaft is horizontally arranged; the pump shaft forward end is rotatably positioned in the sleeve so as to be supported by the bearing assembly; the rear end of the pump shaft is fixedly connected with a motor shaft of the built-in motor so as to be driven by the built-in motor to rotate. The inducer is arranged in the front-section pump shell and is fixedly connected with the front end of the pump shaft. The five impellers are arranged in the middle pump shell; the peripheries of the other four impellers except the final-stage impeller 22 are all sleeved with one guide vane; be provided with bush 5 of fixing on the stator between stator and the impeller, the outer fringe and the middle section pump case inner wall of stator pass through key fixed connection for stator and middle section pump case do not have relative rotation, have relative rotation between stator and the impeller. The balance disc is installed on the pump shaft and fixed on the rear side of the last-stage impeller and used for balancing the axial force on the impeller. The above structures are all existing structures. The utility model discloses an improvement part lies in:

as shown in figure 1, each impeller is fixed on the pump shaft through a group of locating sleeve assemblies 3, machining of the pump shaft is not needed, and machining errors can be reduced. As shown in fig. 2, each set of the positioning sleeve assembly includes a positioning sleeve nut section 13, a positioning sleeve bolt section 12 and a positioning sleeve pin section 11 which are coaxially arranged. The positioning sleeve nut section, the positioning sleeve bolt section and the positioning sleeve pin section are all sleeved on the pump shaft and are sequentially and fixedly connected; the positioning sleeve bolt section is in interference fit with the pump shaft, so that the positioning sleeve bolt section is fixed on the pump shaft; the positioning sleeve bolt section is fixedly connected with the positioning sleeve nut section through a thread pair (an internal thread is arranged on the inner wall of the positioning sleeve nut section, and an external thread matched with the internal thread is arranged on the outer wall of the positioning sleeve bolt section).

The positioning sleeve nut section is fixedly connected with one side of the impeller into a whole through a threaded fastener (preferably a screw); the positioning sleeve pin section, the positioning sleeve bolt section and the other side of the impeller are fixedly connected into a whole through a threaded fastener (preferably a screw). The same number of threaded holes are symmetrically distributed on two sides of the impeller to offset axial force generated by the threaded fasteners on the two sides of the impeller, so that the impeller is ensured not to slide axially. Preferably, the number of threaded holes on each side of the impeller is 4-8 (6 in the figure).

In order to adapt to a low-temperature working environment, the positioning sleeve bolt section and the positioning sleeve nut section are made of austenitic deep-cooling steel, and along with the reduction of temperature, the positioning sleeve bolt section and the positioning sleeve nut section can be connected with the pump shaft more tightly by utilizing the thermal expansion coefficients of the positioning sleeve bolt section and the positioning sleeve nut section. The locating sleeve pin section is made of 9 nickel steel, the thermal expansion coefficient of the locating sleeve pin section is low, and the locating sleeve pin section can ensure that the locating sleeve assembly is more difficult to rotate relatively at low temperature along with the reduction of the locating sleeve bolt section. Compared with the normal temperature, the material can ensure the connection stability of all the parts in the positioning sleeve component in the low-temperature environment, thereby being better suitable for the low-temperature working environment.

In order to guarantee at the installation, the screw of impeller, the screw of position sleeve nut section and the screw of position sleeve round pin section can correspond each other to make things convenient for threaded fastener to screw up, the utility model discloses a following structure:

the tail end of the internal thread of the positioning sleeve nut section is provided with a bulge (not shown in the figure); the initial end of the external thread of the positioning sleeve bolt section is provided with a groove (not shown) matched with the bulge. During installation, the positioning sleeve nut section and the positioning sleeve bolt section are screwed up through the thread pair and the protrusion and the groove are matched with each other, so that the threaded hole of the positioning sleeve nut section is corresponding to the threaded hole of the impeller.

And a positioning sleeve flat key 4 is arranged on the periphery of the positioning sleeve bolt section. When the impeller is installed, the impeller is positioned at the periphery of the positioning sleeve bolt section through the positioning sleeve flat key, so that the threaded hole of the positioning sleeve bolt section can be ensured to correspond to the threaded hole of the impeller, and the impeller is circumferentially positioned.

The outer wall of the positioning sleeve pin section is provided with a bolt 23 extending forwards; and the inner wall of the bolt section of the positioning sleeve is provided with a slot which is in inserted connection with the plug pin. During installation, the bolt extends into the slot, and the threaded hole of the bolt section of the positioning sleeve can be ensured to correspond to the threaded hole of the pin section of the positioning sleeve.

Finally, it should be noted that the above-mentioned embodiments illustrate only specific embodiments of the invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the invention should be considered as within the scope of the invention.

Claims

The LNG multistage immersed pump comprises a front-section pump shell (17), a middle-section pump shell (14) and a rear-section pump shell (10), a bearing assembly (2) fixed in the front-section pump shell, a built-in motor (9) fixed in the rear-section pump shell, a pump shaft (15) with one end supported by the bearing assembly and the other end fixedly connected with a motor shaft of the built-in motor, an inducer (1) arranged in the front-section pump shell and fixedly connected with the front end of the pump shaft, a plurality of impellers (6) arranged in the middle-section pump shell, a plurality of guide vanes (7) sleeved outside the impellers and fixedly connected with the inner wall of the middle-section pump shell at the outer edges, and a balance disc (8) arranged on the pump shaft and fixed at the rear side of a last-stage impeller (; the method is characterized in that:

each impeller is fixed on the pump shaft through a group of locating sleeve assemblies (3); the locating sleeve assembly comprises a locating sleeve nut section (13), a locating sleeve bolt section (12) and a locating sleeve pin section (11), which are sleeved on the pump shaft and fixedly connected in sequence; the positioning sleeve bolt section is in interference fit with the pump shaft, so that the positioning sleeve bolt section is fixed on the pump shaft; the positioning sleeve bolt section is fixedly connected with the positioning sleeve nut section through a thread pair; the positioning sleeve nut section is fixedly connected with one side of the impeller into a whole through a threaded fastener; the positioning sleeve pin section, the positioning sleeve bolt section and the other side of the impeller are fixedly connected into a whole through a threaded fastener; the pump shaft, the positioning sleeve nut section, the positioning sleeve bolt section, the positioning sleeve pin section and the impeller are coaxially arranged.
2. The LNG multistage immersed pump according to claim 1, characterized in that: the bearing assembly comprises a bearing support frame, a bearing (21) fixed on the bearing support frame and a sleeve (16) fixed in a bearing inner ring; the pump shaft is rotatably positioned in the sleeve; the bearing support frame comprises an inner ring (20) for fixedly mounting a bearing, an outer ring (18) fixed on the inner wall of the front-end pump shell through screws and a plurality of ribs (19) connected between the inner ring and the outer ring in a spoke shape.
3. The LNG multistage immersed pump according to claim 2, characterized in that: the thread pair comprises an internal thread arranged on the inner wall of the nut section of the positioning sleeve and an external thread arranged on the outer wall of the bolt section of the positioning sleeve and matched with the internal thread.
4. The LNG multistage immersed pump according to claim 3, wherein: the tail end of the internal thread of the positioning sleeve nut section is provided with a bulge; the initial end of the external thread of the positioning sleeve bolt section is provided with a groove matched with the protrusion, so that the threaded hole of the positioning sleeve nut section is ensured to be corresponding to the threaded hole of the impeller.
5. The LNG multistage immersed pump according to claim 4, wherein: a positioning sleeve flat key (4) is arranged on the periphery of the positioning sleeve bolt section; the impeller is positioned on the periphery of the positioning sleeve bolt section through the positioning sleeve flat key so as to ensure that the threaded hole of the positioning sleeve bolt section corresponds to the threaded hole of the impeller.
6. The LNG multistage immersed pump according to claim 5, wherein: the outer wall of the pin section of the positioning sleeve is provided with a bolt (23); and the inner wall of the positioning sleeve bolt section is provided with a slot which is matched with the inserted pin in an inserted manner so as to ensure that a threaded hole of the positioning sleeve bolt section corresponds to a threaded hole of the positioning sleeve pin section.
7. The LNG multistage immersed pump according to claim 6, wherein: the threaded holes on the two sides of the impeller are the same in number and are symmetrically distributed so as to offset the axial force generated by the threaded fasteners on the two sides of the impeller.
8. The LNG multistage immersed pump according to claim 7, wherein: the number of the threaded holes on each side of the impeller is 4-8.
9. The LNG multistage immersed pump according to claim 8, characterized in that: the positioning sleeve bolt section and the positioning sleeve nut section are both made of austenitic deep-cooled steel; the locating sleeve pin section is made of 9 nickel steel.